(1) Field of the Invention
The present invention relates to an electrical connector, which may be used for a wire harness in automobiles, and more particularly relates to an electrical connector, in which connecting terminals contained in a housing are locked by a rear holder which is engaged with a rear portion of the housing.
(2) Description of Related Art
In conventional electrical connectors for use in a wire harness, connecting terminals installed within a housing are locked in position by means of flexible locking arms. In general, the locking arms are formed integrally with the housing. Therefore, the housing including the locking arms is liable to be complicated in construction, and a mold for manufacturing the housing becomes very complicated and expensive. Since each locking arms are formed within respective connecting terminal accommodating holes, a width of a locking arm has to be much smaller than a width of a connecting terminal accommodating hole and a sufficiently large locking force could not be attained.
In order to improve the difficulty in manufacturing the housing as well as to increase a size of the locking arms, there has been proposed to form locking arms in a separate rear holder as illustrated in FIGS. 1 and 2. In this known electrical connector, a rear holder c is inserted into an opening b formed in a housing a such that the rear holder is clamped at two positions with respect to the housing a by means of locking means not shown. A first position is a provisional locking position in which the rear holder c is halfway inserted into the housing a, and a second position is a complete locking position in which the rear holder c is completely inserted into the housing a.
At the provisional locking position, a connecting terminal e having an electric wires d connected thereto is inserted into a rectangular hollow portion f of the rear holder c such that a projection i of a locking arm h is engaged with an opening g formed in the connecting terminal e. When the rear holder c is further inserted into the housing up to the complete locking position, front ends j of the locking arms h ride over guide portions k of the housing a and a locking force of the locking arms h is increased.
However, in the known electrical connector, since the rear holder c includes the rectangular hollow portions f, a structure of a mold or tool for manufacturing the rear holder could not be simplified sufficiently. That is to say, the mold must be constructed to have one or more bushings and still has a complicated structure. When it is required to release a locking condition between a locking arm h and a connecting terminal e, a special tool has to be inserted into a rectangular hollow portion f from a rear end of the rear holder c, and thus the rear holder c and connecting terminal e might be injured by the tool.
Similarly, in the known electrical connector having the locking arms integrally formed with the housing, when it is required to remove a connecting terminal from the housing, a special tool has to be inserted into the housing from a rear end of the housing along an electric conductor or from a front end through an opening into which connecting terminals of a corresponding electrical connector have to be inserted, and the locking arm is resiliently bent by the tool to release a locking condition between the locking arm and the connecting terminal. Then, the electrical conductor is pulled to remove the connecting terminal from the housing.
Moreover, each of the above mentioned known electrical connectors is composed of a number conductors connected to a wire harness, connecting terminals and housing, and therefore in order to prevent an erroneous connection of wire harnesses, it is necessary to perform an electrical conduction test. Upon conducting the electrical conduction test, after all the connecting terminals have been inserted into the housing, an electrical conduction testing tool is inserted into the housing from the front side opening through which connecting terminals of a corresponding electrical connector are to be inserted into the housing, and the testing tool is engaged with the connecting terminals.
As explained above, in case of releasing a locking condition between a connecting terminal and a locking arm, since the releasing tool must be inserted into the housing from the front side opening of the housing, the inserting operation is liable to be difficult and the housing and connecting terminals might be damaged by the tool. Furthermore, upon performing the electrical conduction test, the testing tool must be inserted into the housing from the front side opening such that the tool is engaged with the connecting terminals, it is required to insert the testing tool with a relatively large force. Furthermore, if connecting terminals of a corresponding electrical connector have been inserted into the housing, it is necessary to remove them before conducting the electrical conduction test.
The present invention has for its object to provide an electrical connector which can mitigate the above mentioned drawbacks and locking arms can be manufactured easily.
It is another object of the invention to provide an electrical connector, in which a clamping force of a locking arm can be improved.
It is another object of the invention to provide an electrical connector, in which a locking condition between a connecting terminal and a locking arm can be easily released through a window formed in a housing.
It is still another object of the invention to provide an electrical connector, an electrical conduction test for a connecting terminal inserted into a housing can be performed easily by means of a window formed in the housing.